[GVN] Set proper debug locations for some instructions created by GVN.

Determining proper debug locations for instructions created in
PHITransAddr is tricky. We use a simple approach here and simply copy
debug locations from instructions computing load address to
"corresponding" instructions re-creating the address computation
in predecessor basic blocks.

This may not always be correct, given all the rearrangement and
simplification going on, and debug locations may jump around a lot,
as the basic blocks we copy locations between may be very far from
each other.

Still, this would work good in most simple cases (e.g. when chain
of address computing instruction is short, or our mapping turns out
to be 1-to-1), and we desire to have *some* reasonable debug locations
associated with newly inserted instructions.

See http://reviews.llvm.org/D10351 review thread for more details.

Test Plan: regression test suite

Reviewers: spatel, dblaikie

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D10351

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239479 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Analysis/PHITransAddr.cpp b/lib/Analysis/PHITransAddr.cpp
index 339f7004af8b4f58bd25009021e987284ddf13f4..8d80c6028ba3d93f6365a41118189aac30e551f5 100644 (file)
--- a/lib/Analysis/PHITransAddr.cpp
+++ b/lib/Analysis/PHITransAddr.cpp
@@ -386,10 +386,10 @@ InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB,
     if (!OpVal) return nullptr;
 
     // Otherwise insert a cast at the end of PredBB.
-    CastInst *New = CastInst::Create(Cast->getOpcode(),
-                                     OpVal, InVal->getType(),
-                                     InVal->getName()+".phi.trans.insert",
+    CastInst *New = CastInst::Create(Cast->getOpcode(), OpVal, InVal->getType(),
+                                     InVal->getName() + ".phi.trans.insert",
                                      PredBB->getTerminator());
+    New->setDebugLoc(Inst->getDebugLoc());
     NewInsts.push_back(New);
     return New;
   }
@@ -408,6 +408,7 @@ InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB,
     GetElementPtrInst *Result = GetElementPtrInst::Create(
         GEP->getSourceElementType(), GEPOps[0], makeArrayRef(GEPOps).slice(1),
         InVal->getName() + ".phi.trans.insert", PredBB->getTerminator());
+    Result->setDebugLoc(Inst->getDebugLoc());
     Result->setIsInBounds(GEP->isInBounds());
     NewInsts.push_back(Result);
     return Result;

diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp
index 7770ddcb9d7a76f6e4d3622aa2e1364c2d9b1af3..17b4bb2629a990f9f85a49dccdf45a5653f0318b 100644 (file)
--- a/lib/Transforms/Scalar/GVN.cpp
+++ b/lib/Transforms/Scalar/GVN.cpp
@@ -1695,6 +1695,8 @@ bool GVN::PerformLoadPRE(LoadInst *LI, AvailValInBlkVect &ValuesPerBlock,
   LI->replaceAllUsesWith(V);
   if (isa<PHINode>(V))
     V->takeName(LI);
+  if (Instruction *I = dyn_cast<Instruction>(V))
+    I->setDebugLoc(LI->getDebugLoc());
   if (V->getType()->getScalarType()->isPointerTy())
     MD->invalidateCachedPointerInfo(V);
   markInstructionForDeletion(LI);
@@ -1761,6 +1763,8 @@ bool GVN::processNonLocalLoad(LoadInst *LI) {
 
     if (isa<PHINode>(V))
       V->takeName(LI);
+    if (Instruction *I = dyn_cast<Instruction>(V))
+      I->setDebugLoc(LI->getDebugLoc());
     if (V->getType()->getScalarType()->isPointerTy())
       MD->invalidateCachedPointerInfo(V);
     markInstructionForDeletion(LI);

diff --git a/test/Transforms/GVN/phi-translate.ll b/test/Transforms/GVN/phi-translate.ll
index 6068b05aadf5c41324cf7c6d760911752fb69942..9e37b882f2223c02e7d3ae14aa5729cbc13dc3f5 100644 (file)
--- a/test/Transforms/GVN/phi-translate.ll
+++ b/test/Transforms/GVN/phi-translate.ll
@@ -4,28 +4,49 @@ target datalayout = "e-p:64:64:64"
 
 ; CHECK-LABEL: @foo(
 ; CHECK: entry.end_crit_edge:
-; CHECK:   %n.pre = load i32, i32* %q.phi.trans.insert
+; CHECK:   %j.phi.trans.insert = sext i32 %x to i64, !dbg [[J_LOC:![0-9]+]]
+; CHECK:   %q.phi.trans.insert = getelementptr {{.*}}, !dbg [[Q_LOC:![0-9]+]]
+; CHECK:   %n.pre = load i32, i32* %q.phi.trans.insert, !dbg [[N_LOC:![0-9]+]]
 ; CHECK: then:
 ; CHECK:   store i32 %z
 ; CHECK: end:
-; CHECK:   %n = phi i32 [ %n.pre, %entry.end_crit_edge ], [ %z, %then ]
+; CHECK:   %n = phi i32 [ %n.pre, %entry.end_crit_edge ], [ %z, %then ], !dbg [[N_LOC]]
 ; CHECK:   ret i32 %n
 
+; CHECK-DAG: [[J_LOC]] = !DILocation(line: 45, column: 1, scope: !{{.*}})
+; CHECK-DAG: [[Q_LOC]] = !DILocation(line: 46, column: 1, scope: !{{.*}})
+; CHECK-DAG: [[N_LOC]] = !DILocation(line: 47, column: 1, scope: !{{.*}})
+
 @G = external global [100 x i32]
 define i32 @foo(i32 %x, i32 %z) {
 entry:
-  %tobool = icmp eq i32 %z, 0
-  br i1 %tobool, label %end, label %then
+  %tobool = icmp eq i32 %z, 0, !dbg !7
+  br i1 %tobool, label %end, label %then, !dbg !7
 
 then:
-  %i = sext i32 %x to i64
-  %p = getelementptr [100 x i32], [100 x i32]* @G, i64 0, i64 %i
-  store i32 %z, i32* %p
-  br label %end
+  %i = sext i32 %x to i64, !dbg !8
+  %p = getelementptr [100 x i32], [100 x i32]* @G, i64 0, i64 %i, !dbg !8
+  store i32 %z, i32* %p, !dbg !8
+  br label %end, !dbg !8
 
 end:
-  %j = sext i32 %x to i64
-  %q = getelementptr [100 x i32], [100 x i32]* @G, i64 0, i64 %j
-  %n = load i32, i32* %q
-  ret i32 %n
+  %j = sext i32 %x to i64, !dbg !9
+  %q = getelementptr [100 x i32], [100 x i32]* @G, i64 0, i64 %j, !dbg !10
+  %n = load i32, i32* %q, !dbg !11
+  ret i32 %n, !dbg !11
 }
+
+!llvm.module.flags = !{!0, !1, !2}
+!0 = !{i32 2, !"Dwarf Version", i32 4}
+!1 = !{i32 2, !"Debug Info Version", i32 3}
+!2 = !{i32 1, !"PIC Level", i32 2}
+
+!3 = !{}
+!4 = !DISubroutineType(types: !3)
+!5 = !DIFile(filename: "a.cc", directory: "/tmp")
+!6 = !DISubprogram(name: "foo", scope: !5, file: !5, line: 42, type: !4, isLocal: false, isDefinition: true, scopeLine: 43, flags: DIFlagPrototyped, isOptimized: false, function: i32 (i32, i32)* @foo, variables: !3)
+!7 = !DILocation(line: 43, column: 1, scope: !6)
+!8 = !DILocation(line: 44, column: 1, scope: !6)
+!9 = !DILocation(line: 45, column: 1, scope: !6)
+!10 = !DILocation(line: 46, column: 1, scope: !6)
+!11 = !DILocation(line: 47, column: 1, scope: !6)